## Top Processes

Different ways to produce top quarks, singly or in pairs.

Common switch for the group of top production.
Scatterings g g → t tbar. Code 601.
Scatterings q qbar → t tbar by gluon exchange. Code 602.
Scatterings q q' → t q'' by t-channel exchange of a W^+- boson. Code 603.
Scatterings f fbar → t tbar by s-channel exchange of a gamma^*/Z^0 boson. Code 604.
Scatterings f fbar' → t q'' by s-channel exchange of a W^+- boson. Code 605.
Scatterings gamma gamma → t tbar. Code 606.
Scatterings g gamma → t tbar. Code 607 when g gamma → t tbar and 617 when gamma g → t tbar.

By default top always decays to a W and a down-type quark. It is possible to switch on the t → H+ b decay mode. Note that its partial width is calculated using the tan(beta) value stored in `HiggsHchg:tanBeta`, so that it can be used without having to read in a SUSY parameter file. For the H+ to decay also `Higgs:useBSM = on` is necessary.